In the related art, as a method of imaging internal information of an object such as a living body or a building, there is a method using X-ray computed tomography (X-ray CT), magnetic resonance imaging (MRI), or positron emission tomography (PET). Specifically, waves, for example, electromagnetic waves such as light, terahertz waves, millimeter waves, or microwaves, or ultrasonic waves are radiated to a living body, an object, or plasma which is an observation target object, scattered waves (reflected waves) thereof are observed and analyzed, and thus internal information of a living body, a solid, or plasma is imaged. In recent years, internal information of a living body or an object has been imaged by using magnetic fields instead of waves.
Generally, such a method employs a technique in which a wave u such as an electromagnetic wave or an ultrasonic wave is radiated to an object O, scattered waves p which are scattered from the object O at a plurality of locations around the object O are observed, and obtained data is imaged (for example, refer to Patent Document 1 and Non-Patent Document 1).
In the technique disclosed in Patent Document 1, internal information of an object is imaged by using an electric wave. Data is repeatedly acquired so as to be imaged while data regarding scattered waves observed by sensor elements disposed on a circumference is being corrected with parameters such as conductivity or permittivity.
The technique disclosed in Non-Patent Document 1 is a technique relating to a multi-path linear array radar, and is to image information regarding defects or the like of concrete. Sensor elements (linear multi-array antenna) which are arranged in a linear or curved shape are disposed on a surface of a target object, scattered waves of radiated waves are observed by the sensors, and observed data is imaged through analysis.
In a medical field, it is expected that an observation method using such waves is used for, for example, a mammography apparatus detecting a breast cancer.